Polarized relay



June 26, 1945; E. DICKTEN; JR

POLARIZED RELAY Original "Filed July' 11, 1940 FIG. 3' V FIG. 2

INVENTOR 1 By Efgf/vrE/v, JR.

ArroR/vr Patented June 26, 1945 POLARIZED RELAY Emil Dickten, Jr., Totowa, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Original application July 11, 1940, Serial N 0. 344,898. Divided and this application March 22, 1944, Serial No. 527,534

4 Claims.

This invention relates to an electromagnetic device and more particularly to a polarized relay of the type covered by my Patent No. 2,355,909 issued on August 15, 1944, of which the present application is a division.

It is often desirable in signaling systems to selectively close either of two work circuits by the operation of 'a polarized relay in response to the energization of its winding by current of either positive or negativ polarity. If a polarized relay of the type which has a single armature biased to a neutral position is used for this type of service, there is always the possibility that if the armature is not accurately so biased it may fail to operate on current of one polarity or may operate falsely due to vibration when the winding is not energized or is energized with a non-operating value of current.

One embodiment of the polarized relay described in the above-mentioned patent is a twoarmature structure having a core that terminates in a. soft iron U-shaped member or yoke which is kept normally saturated by a permanent magnet secured between the legs thereof. An armature is provided on either side of the core which is normally unaffected by the force of the magnet since the armature, being separated by an air-' gap from a leg of the yoke, the latter oifers the flux. of themagnet a path of lower reluctance through itself and the magnet than through the the core produced by the current flowing in one direction opposes the permanent magnet flux in one leg of the yoke and aids the permanent magnet flux in the other leg of the yoke. Because the permanent magnet provides sufiicient flux to normally maintain the iron of the yoke in the region of the non-linear portion of the saturation curve, the net increase in flux in the one leg of the yokewhere it is aided by the coil flux is negligible and the armature adjacent to it i unaffected. In the other leg of the yoke, the permanent magnet flux is opposed by the coil flux and an operating flux passes through the air-gap into the armature adjacent to this leg of the yoke causing it to become operated.

s produced by the current when flowing in the pposite direction affects the respective legs of the yoke oppositely and the other armature is caused to operate. Thus each armature of the relay is subjected to magnetic influence only when current flows through the coil and not otherwise, resulting thereby in a rugged and efiicient polarized relay.

The object of the present invention is to provide a relay structure of the same general polarized type as that described in the above-mentioned patent except that the armatures thereof are of the sealed-in contact type.

For a more comprehensive understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a perspective view of a relay embodying the invention; I

Fig.2 shows, in cross-section, a mercury type switch element applicable to the relay as an armature thereof; and I Fig. 3 shows, in cross-section, a magnetic type switch element which is also applicable to the relay as an armature thereof.

Referring now to Fig. l, the relay comprises a supporting member or heel-piece 35 having a rear upturned ear 36 by which the relay may he supported on a relay mounting rack, and two ears 3! upturned on each side from the rear edges of the member 35 for supporting pile-ups of terminal lugs. Each pile-up comprises three T- shaped lugs 38 which serve as terminals to which the terminals of the coil 39 and the terminals of the switch elements 40 and 4| may be connected. The terminal lugs of these pile-ups are secured to the outer faces of the ears 3'! by screws 42 which extend through holes in the clamping plate 43, in the lugs 38 and into threaded holes in the ears 31, the lugs being insulated from the-ears 31, from the plates 43 and from each other by interposed strips of insulating material, and further insulated from the screws 42 by the usual sleeves of insulating material which surround the screws.

The forward end of the supporting member 35 is widened out to form a lower pole-piece -44. Supported upon the member 35 intermediate its ends is a vertically extending core upon which the coil 39 is mounted and upon the upper end of the core the member 45 is secured both. member 45 and core 39 being secured to the member 35 by the screw 46 or other suitable means. Secured by its base to the outwardly extending end of member 45 by screw is an iron yoke ,the

The direction of the flux through the core which 5 downwardly extending legs 48 and of which are bent outwardly at right angles to form two upper pole-pieces 50 and 5| which lie in a plane parallel to the plane of the lower pole-piece 44. For maintaining the pole-pieces and 5| properly spaced from the pole-piece 44, and to lend rigidity to the pole-pieces, a brace 52 of non-magnetic material is interposed between the members 35 and 45. The upper end of the brace is provided 'with lugs 53 engaged between the shoulders 54 of the member 52 and the rear edge of the yoke 41 while the lower end of the brace is provided with lugs which engage in notches in the edges of the men1 ber 35 for holding the brace in its assembled position. Suitably secured between the legs 43 and 49 of the yoke 41 is a permanent bar magnet 56. The yok 41 serves as a keeper for magnet 56 and is so proportioned that it is normally practically saturated by the flux flowing therethrough from the magnet 56.

The pole-pieces 44, 50 and 5| are provided with aligned embossed holes in which are positioned two sealed switch elements 40 and 4| which function as armatures and contact-closing means. These elements may be of any desired magnetically operable type, two such types suitable for use in the relay structure being disclosed in Figs. 2 and 3.

The armature-contact element disclosed in Fig. 2 may be of the type disclosed in Patent No. 2,247,493 issued to H. C. Harrison and C. E. Pollard on July 1, 1941. This element comprises a tubular glass vessel 51 into the upper and lower ends of which are sealed the terminals 59 and 56. The lower portion of the vessel is filled with a pool of mercury 60 into which the inner end of the lower terminal 58 extends and upon which an annular iron armature 6| floats. The inner end of the upper terminal 59 extends downwardly inside of the armature 6| to a point just above the surface of the mercury pool. Preferably, the vessel 51 is evacuated before it is sealed and is refilled with a gas such as hydrogen. If switch elements of this type are used in the relay, they are so positioned in the aligned holes in the pole-pieces thereof that the lower ends of their armatures 6| are positioned above the lower pole-piece 44 as disclosed in Fig. 2.

This relay, if provided with switch elements of the type just described, functions as follows: The normally permanent magnet flux flows through the yoke 41 and the operating flux produced by the energization of the coil 39 will tend to flow from the pole-piece 50 to the polepiece 44 across the air-gaps between the armature 6| and the pole-pieces. The force due to the flux operates the armature 6| downwardly against the surface tension and buoyancy oi the mercury and thereby displaces the mercury upwardly into engagement with the upper terminal 59 to interconnect the terminals 58 and 59 through the mercury if current flows, say, in one direction through the coil 39 to operate the armature of switch element 40, or to cause coil flux to flow from the pole-piece 44 to the polepiece 5| to similarly operate the armature of the switch element 4| to interconnect its terminal if current flows through coil 39 in the reverse direction through the coil.

The switch elements 40 and 4| may also be of the type disclosed, as another example, in Patent No. 2,289,830 issued to W. B. Ellwood on July 14, 1942. This switch element, disclosed in Fig. 3, comprises a glass vessel 62 into the upper and lower ends of which are sealed the terminals 64 and 63 to the inner ends of which are welded the reeds 66 and 65, respectively, of magnetic material. The overlapping ends of these reeds are normally out of engagement and may be provided with contact surfaces of any suitable metal having good electrical conductivity. The vessel is evacuated before it is sealed and is refilled with a gas such as helium or any other suitable inert gas. If switch elements of this type are used in the relay, they are so positioned in the aligned holes in the pole-pieces thereof that the gaps between the ends of the reeds 65 and 66 are centrally located with respect to the upper and lower pole-pieces as disclosed in Fig. 3.

With the relay shown in Fig. l equipped with switch elements of this type, when the coil 39 is energized by current of one polarity, flux will flow from the pole-piece 50 to the pole-piece 44 across the air-gap between the reeds 66 and 65, and the reeds will be attracted toward each other into contact engagement if current flows in one direction through the coil 39, r the flux will flow from pole-piece 5| to the pole-piece 44 to similarly operate the reeds of the switch elements 4| into engagement if current flows in the reverse direction through the coil.

From the foregoing discussion it will be apparent that a relay structure, which may take other forms besides the one illustrated and described, has been devised which permits simple, compact and inexpensive mechanical construction since only a small bar magnet and a small yoke, or keeper, is required to direct operating flux to either one of two working gaps; that a relay structure is provided which produces a pull on the armature which is essentially proportional to the square of the operating current, thus permitting easy adjustment when close operate and non-operate requirements must be met, and whereby a small change in current produces a large change in pull compared with the usual polarized relay having a pull directly proportional to the operating current; that a relay structure is provided which is not subject to false operation even on excess current, and that the provision of a permanent magnet with a yoke, or keeper, produces an ideal magnetic condition in which the permanent magnet has no tendency to demagnetize and thus destroy the efficiency of the relay, and in which the armatures of the relay are normally not subject to the force of the magnet.

While a permanent magnet has been disclosed bridged across the legs of the yoke 41, it is to be observed that such a magnet could be replaced by an elec'tromagnet so designed as to supply saturating flux to the yoke.

What is claimed is:

1, In a magnetic structure, a core, parallelly disposed polar extensions therefor, a yoke of magnetic material secured to the free end of one 0| said extensions having the ends of its depending arms extended parallel to the end of the other of said extensions, a permanent magnet interconnecting the legs of said yoke, sealed magnetically operable switching elements disposed in aligned openings in the extensions of said yoke legs and in said other polar extension and a coil on said core energizable to cause the selective operation of said switch elements dependent upon the polarity of the current applied to said coil.

2. In a magnetic structure, a core, parallelly disposed polar extensions therefor, a yoke of magnetic material secured to the free end of one of said extensions having the ends of its depending arms extended parallel to the end of the other of said extensions, a permanent magnet interconnecting the legs of said yoke, switching elements disposed in aligned openings in the extensions of said yoke legs and in said other polar extension, each of said elements comprising a sealed vessel having therein a movable armature and contacts engageable by the movement of said armature, and a coil on said core energizable to cause the selective operation of said switch elements dependent upon the polarity of the current applied to said coil,

3. In a magnetic structure, a core, parallelly disposed polar extensions therefor, a yoke of magnetic material secured to the free end of one of said extensions having the ends of its depending arms extending parallel to the end of the other of said extensions, a permanent magnet interconnecting the legs of said yoke, switching elements disposed in aligned openings in the extensions of said yoke legs and in ,said other polar extension, each of said elements comprising a sealed vessel having therein a pool of mercury, an armature floated on the pool of mercury and contacts engageable through said mercury by the displacement of said mercury upon the movement of said armature and a coil on said core energizable to cause the selective operation of said switch elements dependent upon the polarity of the current applied to said coil.

4. In a magnetic structure, a core, parallelly disposed polar extensions therefor, a yoke of magnetic material secured to the free end of one of said extensions having the ends of its depending legs extending parallel to the end of the other of said extensions, a permanent magnet interconnecting the legs of said yoke, switching elements disposed in aligned openings in the extensions of said yoke legs and in said other polar extension, each of said elements comprising a sealed vessel having two terminals sealed through the ends of said vessel and reeds of magnetic material secured Within said vessel to the inner ends of said terminals with their free ends overlapping and normally out of engagement and a coil on said core energizable to cause the selective attraction of the reeds of said switch elements dependent upon the polarity of the current applied to said coil. p

EMIL DICKTEN, JR. 

